JP2019186116A - Power storage device - Google Patents

Abstract

To provide a power storage device capable of improving battery performance.SOLUTION: A power storage device 1 includes a cell stack 2 including multiple power storage cells laminated in the lamination direction via a collector plate. Each of the multiple power storage cells has multiple electrodes laminated in the lamination direction, and a holding member for holding the multiple electrodes. The power storage cell 7A is placed between a positive electrode collector plate 15 and a negative electrode collector plate 16 in the lamination direction. The positive electrode collector plate 15 has a body part in contact with a first face of the power storage cell 7A in the lamination direction, and a positive electrode tab 15b projecting from the body part in the height direction and extending in the lamination direction, the positive electrode tab 15b is placed on the holding member 9A of the power storage cell 7A, and the holding member 9A has projections 91A, 92A for defining th position of the positive electrode tab 15b in the width direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power storage device.

  As a conventional power storage device, for example, an assembled battery described in Patent Document 1 is known. The assembled battery described in Patent Document 1 includes a plurality of bipolar secondary batteries, a plurality of negative electrode collector electrodes, and a plurality of positive electrode collector electrodes. In this assembled battery, a negative electrode current collecting electrode is provided on one main surface of the bipolar secondary battery, and a positive electrode current collecting electrode is provided on the other main surface.

JP 2008-27661 A

  In the assembled battery (power storage device) described in Patent Document 1, when the position of each collecting electrode is shifted with respect to the bipolar battery, the contact area between the bipolar battery and the collecting electrode is reduced, and the bipolar battery and the collecting electrode The resistance component increases in the conductive path between the two. Thereby, there exists a possibility that battery performance may fall.

  An object of the present invention is to provide a power storage device capable of improving battery performance.

  A power storage device according to one aspect of the present invention includes a cell stack including a plurality of power storage cells stacked along a first direction via a current collector plate. Each of the plurality of power storage cells includes a plurality of electrodes stacked along the first direction and a holding member that holds the plurality of electrodes. The 1st electrical storage cell of a plurality of electrical storage cells is arranged between the 1st current collection board and the 2nd current collection board in the 1st direction. The first current collector plate is in contact with the first body portion in contact with the first surface of the first storage cell in the first direction, and protrudes along the second direction intersecting the first direction from the first body portion and the first current collector plate. A first tab extending along the direction. The first tab is disposed on the first holding member of the first power storage cell. The first holding member has a first defining portion that defines the position of the first tab in a third direction intersecting the first direction and the second direction.

  In this power storage device, the first main body portion of the first current collector plate contacts the first surface of the first power storage cell, protrudes from the first main body portion along the second direction, and extends along the first direction. 1 tab is arrange | positioned on the 1st holding member of a 1st electrical storage cell. For this reason, since the first tab contacts the first holding member in the second direction, the position of the first tab in the second direction is defined. Further, the position of the first tab in the third direction is defined by the first defining portion of the first holding member. Thereby, since the position in the 2nd direction and the 3rd direction of the 1st current collecting plate is specified, it is controlled that the position of the 1st body part shifts to the 1st surface of the 1st electrical storage cell. Therefore, an increase in resistance component is suppressed in the conductive path between the first power storage cell and the first current collector plate. As a result, the battery performance of the power storage device can be improved.

  The first tab may have an end surface in the third direction. The first holding member may have a protrusion that protrudes along the second direction and faces the end surface in the third direction. The first defining portion may be a protruding portion. In this case, the position of the first current collector plate in the third direction is defined by the end surface of the first tab coming into contact with the protruding portion of the first holding member. Thereby, it can suppress more reliably that the position of a 1st main-body part shifts | deviates with respect to the 1st surface of a 1st electrical storage cell.

  The first holding member may be provided with a recess that fits into the first tab. The first defining portion may be a recess. In this case, since the first tab and the recess of the first holding member are fitted, the position of the first current collector plate in the third direction is defined. Thereby, it can suppress more reliably that the position of a 1st main-body part shifts | deviates with respect to the 1st surface of a 1st electrical storage cell.

  The second current collector plate is in contact with a second surface opposite to the first surface in the first direction of the first power storage cell, and protrudes along the second direction from the second main body portion and the second current collector plate. And a second tab extending in one direction. The second tab may be disposed on the first holding member. The first holding member may have a second defining portion that defines the position of the second tab in the third direction. In this case, since the second tab contacts the first holding member in the second direction, the position of the second tab in the second direction is defined. Further, the position of the second tab in the third direction is defined by the second defining portion of the first holding member. Thereby, since the position in the 2nd direction and the 3rd direction of the 2nd current collection board is specified, it is controlled that the position of the 2nd body part shifts to the 2nd surface of the 1st electrical storage cell. Therefore, an increase in resistance component is suppressed in the conductive path between the first power storage cell and the second current collector plate. As a result, the battery performance of the power storage device can be further improved.

  The second power storage cell among the plurality of power storage cells may be adjacent to the first power storage cell via the second current collector plate in the first direction. The second current collector plate is in contact with a second surface opposite to the first surface in the first direction of the first power storage cell, and protrudes along the second direction from the second main body portion and the second current collector plate. And a second tab extending in one direction. The second tab may be disposed on the second holding member of the second power storage cell. The second holding member may have a second defining portion that defines the position of the second tab in the third direction. In this case, since the second tab contacts the second holding member in the second direction, the position of the second tab in the second direction is defined. The position of the second tab in the third direction is defined by the second defining portion of the second holding member. Thereby, since the position in the 2nd direction and the 3rd direction of the 2nd current collection board is specified, it is controlled that the position of the 2nd body part shifts to the 2nd surface of the 1st electrical storage cell. Therefore, an increase in resistance component is suppressed in the conductive path between the first power storage cell and the second current collector plate. As a result, the battery performance of the power storage device can be further improved.

  The power storage device extends along the first direction, extends in the second direction, joined to the first tab in the second direction, and joins the second tab in the second direction. And a second bus bar. Since the position of the first current collector plate in the third direction is defined with respect to the first power storage cell, the first power storage cell and the first current collector plate can move together in the third direction. For this reason, even if force is applied to the first power storage cell along the third direction by vibration, it is difficult to move in the third direction. Thereby, the shear stress added to the junction part of a 1st bus bar and a 1st tab along a 3rd direction can be reduced. For the same reason, the shear stress applied along the third direction at the joint between the second bus bar and the second tab can be reduced. As a result, the vibration resistance of the power storage device can be improved.

  The length of the first main body portion in the third direction may be smaller than the length of the first holding member in the third direction. In this case, since the position of the first current collector plate in the third direction is defined with respect to the first holding member, the possibility that the first main body protrudes from the first holding member along the third direction is reduced. be able to. Thereby, it becomes possible to reduce the possibility of electric leakage and a short circuit through the first current collecting plate.

  The length of the first main body portion in the third direction may be equal to the length of the plurality of electrodes in the third direction. A restraining force may be applied to the cell stack along the first direction. When viewed from the first direction, when the first main body overlaps with the first holding member, a binding force is also applied to the first holding member via the first main body, and accordingly, a binding force applied to the cell stack. Need to be larger. In the above configuration, the length of the first main body portion in the third direction is equal to the length of the plurality of electrodes in the third direction, and the position of the first current collector plate in the third direction is defined with respect to the first holding member. Therefore, it is possible to reduce the possibility that the first holding member and the first main body overlap each other when viewed from the first direction. Thereby, the force applied to the first holding member can be reduced, and the restraining force applied to the cell stack can be reduced.

  According to the present invention, the battery performance of the power storage device can be improved.

FIG. 1 is a schematic perspective view showing a power storage device according to an embodiment. FIG. 2 is a plan view partially showing the power storage device shown in FIG. FIG. 3A and FIG. 3B are perspective views showing the storage cell shown in FIG. 2 together with a positive electrode current collector plate and a negative electrode current collector plate. FIG. 4 is a cross-sectional view of the storage cell shown in FIG. 5 is a cross-sectional view taken along line VV in FIG. 6 is a sectional view taken along line VI-VI in FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a process diagram showing a method of manufacturing the power storage device shown in FIG. FIG. 9 is a cross-sectional view of the power storage device according to the first modification. FIG. 10 is a plan view partially showing a power storage device according to a second modification. FIG. 11A and FIG. 11B are perspective views showing the electricity storage cell shown in FIG. 10 together with the positive electrode current collector plate and the negative electrode current collector plate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and redundant descriptions are omitted. In the drawing, an XYZ orthogonal coordinate system is shown as necessary.

  FIG. 1 is a schematic perspective view showing a power storage device according to an embodiment. FIG. 2 is a plan view partially showing the power storage device shown in FIG. FIG. 3A and FIG. 3B are perspective views showing the storage cell shown in FIG. 2 together with a positive electrode current collector plate and a negative electrode current collector plate. FIG. 4 is a cross-sectional view of the storage cell shown in FIG. 5 is a cross-sectional view taken along line VV in FIG. 6 is a sectional view taken along line VI-VI in FIG. The power storage device 1 shown in FIG. 1 is used as a battery for various vehicles such as forklifts, hybrid cars, and electric cars. The power storage device 1 includes a cell stack 2, a pair of end plates 3, a positive bus bar 4 (first bus bar), a negative bus bar 5 (second bus bar), and a cover member 6.

  The cell stack 2 is configured by stacking a plurality of power storage cells 7. The cell stack 2 is an aggregate of about 100 storage cells 7, for example. In the following description, the stacking direction of the storage cells 7 is the X-axis direction (first direction), the width direction of the storage cells 7 is the Y-axis direction (third direction), and the height direction of the storage cells 7 is the Z-axis direction. (Second direction). In the following description, the stacking direction of the storage cells 7 is simply expressed as “stacking direction”, the width direction of the storage cells 7 is simply expressed as “width direction”, and the height direction of the storage cells 7 is simply expressed as “height direction”. .

  The storage cell 7 is a single battery having a flat, substantially rectangular parallelepiped shape. The storage cell 7 may be a secondary battery such as a nickel hydride secondary battery or a lithium ion secondary battery, or may be an electric double layer capacitor. The storage cell 7 may be an all-solid battery. In this embodiment, the case where the electrical storage cell 7 is a bipolar type lithium ion secondary battery is illustrated. As shown in FIG. 2, in the present embodiment, the plurality of power storage cells 7 includes a plurality of power storage cells 7A (first power storage cells), a plurality of power storage cells 7B (second power storage cells), as will be described later. ,including. The storage cells 7A and the storage cells 7B are alternately arranged along the stacking direction one by one. Note that a portion common to the storage cell 7A and the storage cell 7B will be described as the storage cell 7 without distinguishing between the storage cell 7A and the storage cell 7B.

  The electrical storage cell 7 has the electrode laminated body 8 and the holding member 9, as FIG.3 (a), FIG.3 (b), and FIG. 4 show. The electrode laminate 8 has a structure in which a plurality of bipolar electrodes 10 are laminated via separators 11. The plurality of bipolar electrodes 10 are stacked along the stacking direction. The bipolar electrode 10 has a current collector 12, a positive electrode layer 13 formed on one surface of the current collector 12, and a negative electrode layer 14 formed on the other surface of the current collector 12. .

  The current collector 12 is a sheet-like conductive member having a substantially rectangular shape. The current collector 12 is, for example, a metal foil or an alloy foil. Examples of the metal foil include copper foil, aluminum foil, titanium foil, and nickel foil. When the current collector 12 is a metal foil, an aluminum foil may be used as the current collector 12 from the viewpoint of securing mechanical strength. Examples of the alloy foil include a stainless steel foil or an alloy foil of the above metal. When the current collector 12 is a metal foil other than the alloy foil and the aluminum foil, the surface of the current collector 12 may be coated with aluminum.

  The positive electrode layer 13 includes a positive electrode active material and an electrolyte. The positive electrode active material is, for example, a composite oxide, metallic lithium or sulfur. The composition of the composite oxide includes, for example, at least one of manganese, titanium, nickel, cobalt, and aluminum and lithium. The electrolyte is, for example, a solid electrolyte, a solid polymer electrolyte, or a gel electrolyte. The solid electrolyte includes zirconia or β-alumina. The solid polymer electrolyte includes, for example, an alkylene oxide polymer compound such as polyethylene oxide (PEO) and polypropylene oxide (PPO), or a copolymer thereof. A gel electrolyte is an electrolyte that does not exhibit fluidity completely or exhibits fluidity almost completely. For example, the viscosity of the gel electrolyte at 20 ° C. is 0.1 Pa · S or more.

When the positive electrode layer 13 includes a solid polymer electrolyte, the positive electrode layer 13 is, for example, at least one of a supporting salt for increasing ionic conductivity, a conductive assistant for increasing electron conductivity, a viscosity adjusting solvent, and a polymerization initiator. Including The supporting salt is, for example, a lithium salt from the viewpoint of being easily soluble in the alkylene oxide polymer compound. The lithium salt is, for example, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof. The conductive auxiliary agent is, for example, acetylene black, carbon black, or graphite. The viscosity adjusting solvent is, for example, N-methyl-2-pyrrolidone (NMP). Examples of the polymerization initiator include azobisisobutyronitrile (AIBN).

  The negative electrode layer 14 includes a negative electrode active material and an electrolyte. The negative electrode active material is, for example, graphite, highly oriented graphite, mesocarbon microbeads, carbon such as hard carbon or soft carbon, alkali metals such as lithium or sodium, metal compounds, elements that can be alloyed with lithium, or compounds thereof, or For example, boron-added carbon. Examples of elements that can be alloyed with lithium include silicon (silicon) and tin. The electrolyte of the negative electrode layer 14 is the same as the electrolyte contained in the positive electrode layer 13, for example.

  The separator 11 is a layered member that separates the bipolar electrodes 10 adjacent to each other, and has a substantially rectangular shape. The separator 11 is composed of an electrolyte contained in the positive electrode layer 13 and the negative electrode layer 14. The separator 11 may be a porous film that can be filled with an electrolyte. When the separator 11 is formed of a solid electrolyte, the separator 11 may have a substantially rectangular plate shape.

  Current collectors 12 are respectively provided at both ends of the electrode stack 8 in the stacking direction. Only the positive electrode layer 13 is formed on the current collector 12 positioned at one end of the electrode laminate 8 (the right end in FIG. 4), and this current collector 12 functions as a positive electrode terminal of the storage cell 7. . Only the negative electrode layer 14 is formed on the current collector 12 positioned at the other end of the electrode laminate 8 (the left end in FIG. 4). The current collector 12 functions as the negative electrode terminal of the storage cell 7. To do.

  The holding member 9 is a member that holds the electrode stack 8 (a plurality of bipolar electrodes 10). The holding member 9 has a rectangular frame shape surrounding both side surfaces, top surfaces, and bottom surfaces of the electrode laminate 8 in the width direction. The holding member 9 is made of, for example, a resin having insulating properties and heat resistance. Examples of the resin forming the holding member 9 include polyimide, polypropylene (PP), polyphenylene sulfide (PPS), and nylon 66 (PA66). The holding member 9 has a function of sealing the bipolar electrode 10 and preventing a short circuit between the bipolar electrodes 10.

  The plurality of power storage cells 7 are stacked via alternating positive electrode current collector plates 15 (first current collector plates) and negative electrode current collector plates 16 (second current collector plates). The positive electrode current collector plate 15 and the negative electrode current collector plate 16 are metal plates having a rectangular shape substantially the same shape as the main surface of the storage cell 7. The main surface of the storage cell 7 is a pair of surfaces intersecting the stacking direction of the electrode stack 8, specifically, the outer surface of the current collector 12 positioned at both ends of the electrode stack 8 in the stacking direction. . The positive electrode current collector plate 15 and the negative electrode current collector plate 16 are made of, for example, the same metal material as that of the current collector 12. The positive electrode current collector plate 15 and the negative electrode current collector plate 16 are disposed so as to sandwich the storage cell 7 in the stacking direction. The positive electrode current collector plate 15 is in contact with the outer surface 12 a (first surface) of the current collector 12 that functions as the positive electrode terminal of the storage cell 7. The negative electrode current collector plate 16 is in contact with the outer side surface 12 b (second surface) of the current collector 12 that functions as the negative electrode terminal of the storage cell 7.

  The positive electrode current collector plate 15 has a main body 15a (first main body) having a rectangular shape in plan view, and a positive electrode tab 15b (first tab) integrated with the main body 15a. The main body portion 15a is in contact with the outer surface 12a of the current collector 12 that functions as a positive electrode terminal. The main body portion 15a has substantially the same shape as the outer surface 12a, and overlaps the outer surface 12a in the stacking direction. The width Wp (length in the width direction) of the main body portion 15a is smaller than the width Wc (length in the width direction, see FIG. 7) of the holding members 9A and 9B (power storage cells 7A and 7B). The width Wp of the main body 15a is equal to the width We (length in the width direction, see FIG. 7) of the outer surface 12a (electrode stack 8). The width Wp being equal to the width We includes not only the case where the width Wp and the width We are completely the same, but also the case where the width Wp and the width We are substantially the same. “Substantially the same” means that the design values are the same, and may differ depending on manufacturing tolerances.

  The positive electrode tab 15 b is joined to the positive electrode bus bar 4. The positive electrode tab 15b protrudes along the height direction from the main body 15a and extends along the stacking direction. Specifically, the positive electrode tab 15b protrudes in the height direction with respect to the electrode laminate 8 on one side in the width direction. The tip of the positive electrode tab 15b is bent outward from the power storage cell 7B and extends toward the power storage cell 7A. The positive electrode tab 15b is disposed on the top surface 9a of the holding member 9A (first holding member).

  The bent portion of the positive electrode tab 15b of each positive electrode current collector plate 15 is aligned facing one side in the stacking direction. And the positive electrode bus bar 4 is joined to the bending part of the positive electrode tab 15b of each positive electrode current collecting plate 15 by welding etc. (refer FIG. 5). The positive electrode current collector plate 15 and the positive electrode bus bar 4 are joined by a welded portion W1. The positive electrode tab 15b has an end face 15c (see FIG. 7) and an end face 15d (see FIG. 7) in the width direction. The end surface 15 c is a surface facing the inside of the power storage device 1. The end surface 15 d is a surface opposite to the end surface 15 c and faces the outside of the power storage device 1. The width of the positive electrode tab 15b is smaller than half the width Wp of the positive electrode current collector plate 15, and the width of the positive electrode tab 15b of each positive electrode current collector plate 15 is equal to each other.

  The negative electrode current collector plate 16 has a main body 16a (second main body) having a rectangular shape in plan view, and a negative electrode tab 16b (second tab) integrated with the main body 16a. The main body portion 16a is in contact with the outer surface 12b of the current collector 12 that functions as a negative electrode terminal. The main body portion 16a has substantially the same shape as the outer surface 12b, and overlaps the outer surface 12b in the stacking direction. The width Wn (length in the width direction) of the main body portion 16a is equal to the width Wp and is smaller than the width Wc of the holding members 9A and 9B (power storage cells 7A and 7B). The width Wn of the main body portion 16a is equal to the width We of the outer surface 12b (electrode stack 8). The width Wn being equal to the width We includes not only the case where the width Wn and the width We are completely the same, but also the case where the width Wn and the width We are substantially the same. “Substantially the same” means that the design values are the same, and may differ depending on manufacturing tolerances.

  The negative electrode tab 16 b is joined to the negative electrode bus bar 5. The negative electrode tab 16b protrudes along the height direction from the main body 16a and extends along the stacking direction. Specifically, the negative electrode tab 16b protrudes in the height direction with respect to the electrode laminate 8 on the other side in the width direction. The negative electrode tab 16b protrudes on the same side as the positive electrode tab 15b in the height direction. The tip of the negative electrode tab 16b is bent outward from the electricity storage cell 7B and extends toward the electricity storage cell 7A. The negative electrode tab 16b is disposed on the top surface 9a of the holding member 9A.

  The bending direction of the negative electrode tab 16b is opposite to the bending direction of the positive electrode tab 15b. The bent portion of the negative electrode tab 16b of each negative electrode current collector plate 16 is aligned facing the other side in the stacking direction. And the negative electrode bus-bar 5 is joined with the bending part of the negative electrode tab 16b of each negative electrode current collecting plate 16 by welding etc. (refer FIG. 6). The negative electrode current collector plate 16 and the negative electrode bus bar 5 are joined by a welded portion W2. The negative electrode tab 16b has an end face 16c (see FIG. 7) and an end face 16d (see FIG. 7) in the width direction. The end surface 16 c is a surface facing the inside of the power storage device 1. The end surface 16 d is a surface opposite to the end surface 16 c and faces the outside of the power storage device 1. The width of the negative electrode tab 16b is smaller than half of the width Wn of the negative electrode current collector plate 16, and the width of the negative electrode tab 16b of each negative electrode current collector plate 16 is equal to each other. The negative electrode tab 16b is separated from the positive electrode tab 15b in the width direction.

  As shown in FIG. 2, in the cell stack 2 of the present embodiment, the storage cells 7A and the storage cells 7B are alternately arranged along the stacking direction. That is, the storage cells 7A and 7B are arranged between the positive electrode current collector plate 15 and the negative electrode current collector plate 16 in the stacking direction. A positive electrode current collector plate 15 or a negative electrode current collector plate 16 is disposed between the power storage cells 7A and 7B adjacent to each other in the stacking direction. In other words, the storage cell 7A and the storage cell 7B are adjacent to each other via the positive electrode current collector plate 15 or the negative electrode current collector plate 16. A positive electrode tab 15b and a negative electrode tab 16b are disposed on the holding member 9A (the top surface 9a of the holding member 9A). Neither the positive electrode tab 15b nor the negative electrode tab 16b is disposed on the holding member 9B (second holding member) (the top surface 9a of the holding member 9B). The holding member 9 </ b> A regulates the displacement of the positive electrode current collector plate 15 and the negative electrode current collector plate 16 in the height direction and the width direction. The regulation of displacement of the positive electrode current collector plate 15 and the negative electrode current collector plate 16 by the holding member 9A will be described later.

  The end plate 3 is a restraining member that regulates the displacement of the storage cell 7 in the stacking direction. The end plates 3 are arranged on both sides of the cell stack 2 in the stacking direction. The end plate 3 has an L shape in side view. The end plate 3 is made of, for example, a metal or an alloy. The end plates 3 are connected to each other by a cover member 6, and a restraining load along the stacking direction is applied to the cell stack 2 via the end plate 3. Each end plate 3 may be connected with fastening members, such as a volt | bolt and a nut. In this case, a binding load along the stacking direction is applied to the cell stack 2 via the end plate 3 by the tightening force of the fastening member.

  Insulation buffer members 17 are respectively disposed between the storage cells 7 and the end plates 3 positioned at both ends of the cell stack 2 in the stacking direction. The insulating buffer member 17 is a member having a function of absorbing expansion of the storage cell 7. The insulating buffer member 17 has, for example, a rectangular parallelepiped shape having the same area as the main surface of the storage cell 7 when viewed from the stacking direction. Examples of a material for forming the insulating buffer member 17 include PP, PPS, and PA66.

  Each of the positive electrode bus bar 4 and the negative electrode bus bar 5 extends along the stacking direction, as shown in FIG. The positive electrode bus bar 4 and the negative electrode bus bar 5 are arranged side by side in the width direction on the same side in the height direction with respect to the cell stack 2. Specifically, the positive electrode bus bar 4 is disposed on one side in the width direction on the top surface of the cell stack 2. The negative electrode bus bar 5 is arranged on the other side in the width direction on the top surface of the cell stack 2 so as to be separated from the positive electrode bus bar 4. The positive electrode bus bar 4 is joined to each positive electrode current collector plate 15 (positive electrode tab 15b) in the height direction, and is electrically connected to each positive electrode current collector plate 15. The negative electrode bus bar 5 is joined to each negative electrode current collector plate 16 (negative electrode tab 16b) in the height direction, and is electrically connected to each negative electrode current collector plate 16.

  The positive electrode bus bar 4 and the negative electrode bus bar 5 have a rectangular plate shape, for example. The forming material of the positive electrode bus bar 4 and the negative electrode bus bar 5 may be, for example, a metal such as copper, aluminum, titanium, or nickel, or may be stainless steel or an alloy of the above-described metals.

  An extraction terminal for connecting the cell stack 2 to an external device may be connected to one end in the longitudinal direction of the positive electrode bus bar 4. An extraction terminal for connecting the cell stack 2 to an external device may be connected to one end of the negative electrode bus bar 5 in the longitudinal direction.

  The positive electrode bus bar 4 has an end face 4b (see FIG. 7) and an end face 4c (see FIG. 7) in the width direction. The end surface 4b is a surface facing the end surface of the cover member 6 in the width direction. The end surface 4 c is a surface opposite to the end surface 4 b and faces the outside of the power storage device 1. The negative electrode bus bar 5 has an end face 5b (see FIG. 7) and an end face 5c (see FIG. 7) in the width direction. The end surface 5b is a surface facing the end surface of the cover member 6 in the width direction. The end surface 5 c is a surface opposite to the end surface 5 b and faces the outside of the power storage device 1.

  The cover member 6 is a member for defining the position of the storage cell 7 in the height direction. The cover member 6 extends along the stacking direction. The cover member 6 is made of, for example, a metal or an alloy. The cover member 6 is disposed between the positive electrode bus bar 4 and the negative electrode bus bar 5 in a state of being separated from the positive electrode bus bar 4 and the negative electrode bus bar 5 on the top surface of the cell stack 2. The cover member 6 has a main body portion 6a extending in the stacking direction and a pair of claw portions 6b provided at both ends in the longitudinal direction of the main body portion 6a. The claw portion 6 b is fixed to the outer surface of the end plate 3 by the fastening member E. Thereby, the cover member 6 is locked to the cell stack 2, and a restraining load along the stacking direction is applied to the cell stack 2 via the pair of end plates 3.

  Next, with reference to FIG. 7 further, the regulation of the positional deviation of the positive electrode current collector plate 15 and the negative electrode current collector plate 16 by the holding member 9A will be described. 7 is a cross-sectional view taken along line VII-VII in FIG.

  As shown in FIGS. 2, 3A, and 7, the holding member 9A includes projecting portions 91A, 91B, 92A, and 92B. The protrusions 91A and 92A are provided on the top surface 9a and protrude from the top surface 9a along the height direction. The protrusions 91A and 92A are spaced apart so as to sandwich the positive electrode tab 15b in the width direction. The protrusion 91A is located on the cover member 6 side, and the protrusion 92A is located outside. The protruding portion 91A has a side surface 91a that intersects the width direction. The protrusion 92A has a side surface 92a that intersects the width direction and faces the side surface 91a with the positive electrode tab 15b interposed therebetween. The side surface 91a faces the end surface 15c in the width direction and is in contact with the end surface 15c. The side surface 92a faces the end surface 15d in the width direction and is in contact with the end surface 15d.

  The height (length in the height direction) of the protrusions 91A and 92A is larger than the thickness (length in the height direction) of the positive electrode tab 15b. That is, the upper ends of the protrusions 91A and 92A are higher than the upper surface of the positive electrode tab 15b. Therefore, the protruding portions 91A and 92A sandwich the positive bus bar 4 in the width direction. That is, the side surface 91a faces the end surface 4b in the width direction and is in contact with the end surface 4b. The side surface 92a faces the end surface 4c in the width direction and is in contact with the end surface 4c.

  The protrusions 91B and 92B are provided on the top surface 9a and protrude from the top surface 9a along the height direction. The projecting portions 91B and 92B are spaced apart so as to sandwich the negative electrode tab 16b in the width direction. The protrusion 91B is located on the cover member 6 side, and the protrusion 92B is located outside. The protrusion 91B has a side surface 91b that intersects the width direction. The protruding portion 92B has a side surface 92b that intersects the width direction and faces the side surface 91b through the negative electrode tab 16b. The side surface 91b faces the end surface 16c in the width direction and is in contact with the end surface 16c. The side surface 92b faces the end surface 16d in the width direction and is in contact with the end surface 16d.

  The height (the length in the height direction) of the protrusions 91B and 92B is larger than the thickness (the length in the height direction) of the negative electrode tab 16b. That is, the upper ends of the protrusions 91B and 92B are higher than the upper surface of the negative electrode tab 16b. For this reason, the protruding portions 91B and 92B sandwich the negative electrode bus bar 5 in the width direction. That is, the side surface 91b faces the end surface 5b in the width direction and is in contact with the end surface 5b. The side surface 92b faces the end surface 5c in the width direction and is in contact with the end surface 5c.

  The holding member 9B does not include the protruding portions 91A, 91B, 92A, and 92B, but may include at least one of the protruding portions 91A, 91B, 92A, and 92B.

  As described above, in the power storage device 1, the main body portion 15a of the positive electrode current collector plate 15 contacts the outer surface 12a of the current collector 12 functioning as the positive electrode terminal of the power storage cell 7A, and the positive electrode tab 15b is on the holding member 9A. Is arranged. For this reason, since the positive electrode tab 15b contacts the top surface 9a of the holding member 9A in the height direction and is supported by the top surface 9a, the relative position in the height direction of the positive electrode tab 15b with respect to the storage cell 7A is defined. Is done. Further, since the end surface 15c of the positive electrode tab 15b is in contact with the protrusion 91A and the end surface 15d of the positive electrode tab 15b is in contact with the protrusion 92A, the relative position in the width direction of the positive electrode tab 15b with respect to the storage cell 7A protrudes. Part 91A, 92A. That is, the protruding portions 91A and 92A (side surfaces 91a and 92a) function as a defining portion (first defining portion) that defines the position of the positive electrode tab 15b (positive electrode current collector plate 15) in the width direction. Thereby, since the relative position in the height direction and the width direction of the positive electrode current collector plate 15 is defined with respect to the storage cell 7A, the position of the main body portion 15a is shifted with respect to the outer surface 12a of the storage cell 7A. It is suppressed. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cell 7A and the positive electrode current collector plate 15.

  Similarly, in the power storage device 1, the main body portion 16a of the negative electrode current collector plate 16 contacts the outer side surface 12b of the current collector 12 functioning as the negative electrode terminal of the power storage cell 7A, and the negative electrode tab 16b is disposed on the holding member 9A. ing. For this reason, since the negative electrode tab 16b contacts the top surface 9a of the holding member 9A in the height direction and is supported by the top surface 9a, the relative position in the height direction of the negative electrode tab 16b with respect to the storage cell 7A is defined. Is done. Further, since the end face 16c of the negative electrode tab 16b is in contact with the protruding portion 91B and the end face 16d of the negative electrode tab 16b is in contact with the protruding portion 92B, the relative position in the width direction of the negative electrode tab 16b with respect to the storage cell 7A protrudes. Defined by the portions 91B and 92B. That is, the protruding portions 91B and 92B (side surfaces 91b and 92b) function as a defining portion (second defining portion) that defines the position of the negative electrode tab 16b (negative electrode current collector plate 16) in the width direction. Thereby, since the relative position in the height direction and the width direction of the negative electrode current collector plate 16 with respect to the storage cell 7A is defined, the position of the main body portion 16a is shifted with respect to the outer side surface 12b of the storage cell 7A. It is suppressed. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cell 7A and the negative electrode current collector plate 16.

  Further, in the power storage device 1, since the holding member 9 is aligned in the height direction and the width direction, the main body is respectively formed on the outer surfaces 12a of the power storage cells 7A and 7B adjacent to each other with the main body portion 15a interposed therebetween. The position of the portion 15a is prevented from shifting. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cells 7A and 7B and the positive electrode current collector plate 15. Similarly, the position of the main body portion 16a is suppressed from shifting with respect to each of the outer surfaces 12b of the storage cells 7A and 7B adjacent to each other across the main body portion 16a. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cells 7A and 7B and the negative electrode current collector plate 16.

  The amount of displacement in the width direction of the positive electrode tab 15b with respect to the positive electrode bus bar 4 is the amount of displacement in the width direction of the storage cell 7A with respect to the positive electrode bus bar 4 and the amount of displacement in the width direction of the positive electrode tab 15b with respect to each storage cell 7A. It is calculated by adding up. In the power storage device 1, the position in the width direction of the positive electrode tab 15b is defined with respect to the power storage cell 7A. For this reason, the amount of displacement in the width direction of the positive electrode tab 15 b with respect to the positive electrode bus bar 4 is obtained from the amount of displacement in the width direction of the storage cell 7 A with respect to the positive electrode bus bar 4. Thereby, in the width direction, since the maximum value of the positional deviation amount of the positive electrode tab 15b with respect to the positive electrode bus bar 4 is reduced, an increase in the resistance component is suppressed in the conductive path between the positive electrode bus bar 4 and the positive electrode current collector plate 15. The For the same reason, an increase in the resistance component is suppressed in the conductive path between the negative electrode bus bar 5 and the negative electrode current collector plate 16.

  Therefore, the battery performance of the power storage device 1 can be improved.

  The width Wp of the main body portion 15a and the width Wn of the main body portion 16a are smaller than the width Wc of the holding members 9A and 9B (power storage cells 7A and 7B). The positions in the width direction of the positive electrode current collector plate 15 and the negative electrode current collector plate 16 are defined with respect to the holding member 9A. Moreover, the height direction and the width direction of each holding member 9 are aligned. For this reason, the possibility that the main body portions 15a and 16a protrude from the holding members 9A and 9B to the outside of the power storage device 1 along the width direction can be reduced. Thereby, it becomes possible to reduce the possibility of electric leakage and short circuit through the main body portions 15a and 16a.

  A restraining force is applied to the cell stack 2 along the stacking direction. When the width Wp of the main body 15a is larger than the width We of the electrode stack 8, a restraining force is also applied to the holding member 9 through the main body 15a. Similarly, when the width Wn of the main body portion 16a is larger than the width We of the electrode stack 8, a restraining force is also applied to the holding member 9 via the main body portion 16a. It is necessary to increase the restraining force applied to the cell stack 2 by the amount applied to the holding member 9. In the power storage device 1, the widths Wp and Wn are equal (substantially the same) as the width We, and the positions of the positive electrode current collector plate 15 and the negative electrode current collector plate 16 in the width direction are defined with respect to the holding member 9A. Therefore, when viewed from the stacking direction, the possibility that the holding member 9A and the main body portions 15a and 16a overlap each other can be reduced. Thereby, the force applied to the holding member 9A can be reduced, and the restraining force applied to the cell stack 2 can be reduced.

  The upper end of the protruding portion 91A is higher than the upper surface of the positive electrode tab 15b. For this reason, not only the positive electrode current collecting plate 15 but also the position in the width direction of the positive electrode bus bar 4 can be defined. Similarly, the upper end of the protruding portion 91B is higher than the upper surface of the negative electrode tab 16b. For this reason, not only the negative electrode current collector plate 16 but also the position in the width direction of the negative electrode bus bar 5 can be defined. Further, since the protruding portion 91 </ b> A is interposed between the positive electrode bus bar 4 and the cover member 6, a clearance (separation distance) between the positive electrode bus bar 4 and the cover member 6 can be ensured. Since the protruding portion 92 </ b> B is interposed between the negative electrode bus bar 5 and the cover member 6, a clearance (separation distance) between the negative electrode bus bar 5 and the cover member 6 can be ensured. Thereby, the possibility that the positive electrode bus bar 4 and the negative electrode bus bar 5 are short-circuited via the cover member 6 can be reduced.

  The upper end of the protrusion 92A is higher than the upper surface of the positive electrode tab 15b. For this reason, not only the positive electrode current collecting plate 15 but also the position in the width direction of the positive electrode bus bar 4 can be defined. Further, since the protrusion 92A is interposed between the positive electrode bus bar 4 and the housing, a clearance (separation distance) between the positive electrode bus bar 4 and the housing can be secured. Thereby, possibility that the positive electrode bus bar 4 will contact a housing | casing can be reduced. Similarly, the upper end of the protrusion 92B is higher than the upper surface of the negative electrode tab 16b. For this reason, not only the negative electrode current collector plate 16 but also the position in the width direction of the negative electrode bus bar 5 can be defined. Further, since the protrusion 92B is interposed between the negative electrode bus bar 5 and the housing, a clearance (separation distance) between the negative electrode bus bar 5 and the housing can be ensured. Thereby, possibility that the negative electrode bus bar 5 will contact a housing | casing can be reduced.

  Since the positions of the positive electrode bus bar 4 and the positive electrode current collector plate 15 (positive electrode tab 15b) in the width direction are defined by the protrusions 91A and 92A, the positive electrode tab 15b is prevented from moving in the width direction with respect to the positive electrode bus bar 4. Is done. Thereby, even if force is applied to each power storage cell 7 along the width direction due to vibration, the shear stress applied along the width direction to the welded portion W1 between the positive electrode bus bar 4 and the positive electrode current collector plate 15 can be reduced. it can. Similarly, the positions of the negative electrode bus bar 5 and the negative electrode current collector plate 16 (negative electrode tab 16b) in the width direction are defined by the protrusions 91B and 92B, so that the negative electrode tab 16b moves in the width direction with respect to the negative electrode bus bar 5. It is suppressed. Thereby, even if force is applied to each storage cell 7 along the width direction by vibration, the shear stress applied along the width direction to the welded portion W2 between the negative electrode bus bar 5 and the negative electrode current collector plate 16 can be reduced. it can. As a result, the vibration resistance of the power storage device 1 can be improved.

  Next, a method for manufacturing power storage device 1 will be described with reference to FIG. FIG. 8 is a process diagram showing a method of manufacturing the power storage device shown in FIG.

  As shown in FIG. 8, first, in step S01, the cell stack 2 is formed. Specifically, first, the positive electrode current collector plate 15 and the negative electrode current collector plate 16 are assembled to the storage cell 7A. At this time, the positive electrode tab 15b is inserted between the protruding portion 91A and the protruding portion 92A and disposed on the top surface 9a, and the main body portion 15a is outside the current collector 12 that functions as the positive electrode terminal of the storage cell 7A. It arrange | positions on the side surface 12a. Thereby, the positive electrode current collecting plate 15 is positioned in a state where the main body portion 15a is superimposed on the outer surface 12a in the stacking direction. Similarly, the negative electrode tab 16b is inserted between the protruding portion 91B and the protruding portion 92B and disposed on the top surface 9a, and the main body portion 16a is disposed outside the current collector 12 that functions as the negative electrode terminal of the storage cell 7A. It arrange | positions on the side surface 12b. Thereby, the negative electrode current collecting plate 16 is positioned in a state where the main body portion 16a is superimposed on the outer surface 12b in the stacking direction. Then, the storage cells 7A and the storage cells 7B are alternately arranged one by one along the stacking direction. In this way, the plurality of power storage cells 7 are stacked along one direction through the positive electrode current collecting plates 15 and the negative electrode current collecting plates 16 alternately, and the cell stack 2 is formed.

  Subsequently, in step S02, a pair of end plates 3 are arranged. Specifically, a pair of end plates 3 are disposed on both ends of the cell stack 2 in the stacking direction via insulating buffer members 17.

  Subsequently, in step S03, the positive electrode bus bar 4 and the negative electrode bus bar 5 are arranged. Specifically, the positive electrode bus bar 4 is provided along the stacking direction on one side in the width direction on the top surface of the cell stack 2. More specifically, the positive electrode bus bar 4 is disposed on the top surface of the cell stack 2 so as to be in contact with each of the positive electrode tabs 15 b of the plurality of positive electrode current collector plates 15. Similarly, the negative electrode bus bar 5 is provided on the other side in the width direction on the top surface of the cell stack 2 along the stacking direction. More specifically, the negative electrode bus bar 5 is disposed on the top surface of the cell stack 2 so as to be in contact with each of the negative electrode tabs 16 b of the plurality of negative electrode current collector plates 16.

  At this time, the positive electrode bus bar 4 is fitted between the protruding portion 91A and the protruding portion 92A of the holding member 9A of each storage cell 7A. That is, the end surface 4b of the positive electrode bus bar 4 and the side surface 91a of the protruding portion 91A are in contact with each other, and the end surface 4c of the positive electrode bus bar 4 and the side surface 92a of the protruding portion 92A are in contact with each other. Similarly, the negative electrode bus bar 5 is fitted between the protruding portion 91B and the protruding portion 92B of the holding member 9A of each storage cell 7A. That is, the end surface 5b of the negative electrode bus bar 5 and the side surface 91b of the protruding portion 91B are in contact with each other, and the end surface 5c of the negative electrode bus bar 5 and the side surface 92b of the protruding portion 92B are in contact with each other. Thereby, the position in the width direction of the plurality of power storage cells 7A is aligned.

  Further, by aligning the bottom surface and the side surface of each holding member 9, relative positions in the height direction and the width direction of the positive electrode current collector plate 15 and the negative electrode current collector plate 16 are also defined for the storage cell 7 </ b> B. That is, the main body portion 15a is overlaid on the outer surface 12a of the storage cell 7B adjacent in the stacking direction, and the main body portion 16a is stacked on the outer surface 12b of the adjacent storage cell 7B in the stacking direction.

  Subsequently, in step S04, the cover member 6 is attached. Specifically, the cover member 6 is disposed on the top surface of the cell stack 2 along the stacking direction between the positive electrode bus bar 4 and the negative electrode bus bar 5. The claw portion 6b is fixed to the outer surface of the end plate 3 by the fastening member E. As a result, a binding load along the stacking direction is applied to the cell stack 2 via the pair of end plates 3.

  Subsequently, in step S05, the positive electrode bus bar 4 and the positive electrode current collector plate 15 (positive electrode tab 15b) are joined by, for example, laser welding. Thereby, the welding part W1 which joins the positive electrode bus bar 4 and the positive electrode tab 15b is formed. Similarly, the negative electrode bus bar 5 and the negative electrode current collector plate 16 (negative electrode tab 16b) are joined by, for example, laser welding. As a result, a welded portion W2 that joins the negative electrode bus bar 5 and the negative electrode tab 16b is formed.

  Through the above steps, the power storage device 1 is manufactured. Note that the order of step S04 and step S05 may be switched. Since the cover member 6 does not necessarily have to be attached, step S04 can be omitted.

  In this method for manufacturing the power storage device 1, when the positive electrode current collector plate 15 is assembled to the power storage cell 7A, the positive electrode current collector 15 is disposed between the protruding portion 91A and the protruding portion 92A of the power storage cell 7A. The position in the height direction and the width direction of the plate 15 (positive electrode tab 15b) is defined. Similarly, when the negative electrode current collector plate 16 is assembled to the electricity storage cell 7A, the negative electrode current collector plate 16 (negative electrode tab 16b is arranged by disposing the negative electrode tab 16b between the protrusion 91B and the protrusion 92B of the energy storage cell 7A. ) In the height direction and width direction. And after arrange | positioning the electrical storage cell 7A and the electrical storage cell 7B alternately along the lamination direction, by aligning the height direction and the width direction of each holding member 9, the several positive electrode current collection board 15 (positive electrode tab in the width direction) is arrange | positioned. 15b) and the positions of the (negative electrode tabs 16b) of the plurality of negative electrode current collector plates 16 are aligned. In this state, the positive electrode bus bar 4 is joined to each of the plurality of positive electrode current collector plates 15, and the negative electrode bus bar 5 is joined to each of the plurality of negative electrode current collector plates 16, so that each positive electrode with respect to the positive electrode bus bar 4 in the width direction. The displacement of the current collector plate 15 can be reduced, and the displacement of the storage cell 7 of each negative electrode current collector plate 16 with respect to the negative electrode bus bar 5 can be reduced. As a result, the assemblability of the power storage device 1 is improved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment.

  For example, in the above-described embodiment, one power storage device 1 includes one positive electrode bus bar 4 and one negative electrode bus bar 5, but is not particularly limited thereto. One power storage device 1 may include a plurality of positive electrode bus bars 4 and a plurality of negative electrode bus bars 5.

  In the above embodiment, the positive electrode bus bar 4 and the negative electrode bus bar 5 are arranged side by side in the width direction on the same side in the height direction with respect to the cell stack 2, but are not limited to this form. The positive electrode bus bar 4 may be disposed on one side in the height direction with respect to the cell stack 2, and the negative electrode bus bar 5 may be disposed on the other side in the height direction with respect to the cell stack 2.

  In the above embodiment, the positive electrode bus bar 4 and the positive electrode current collector plate 15 are joined by welding. However, other methods may be used. The same applies to the joining of the negative electrode bus bar 5 and the negative electrode current collector plate 16.

  The cover member 6 may be formed of an insulating material. Examples of the insulating material forming the cover member 6 include polyimide, PP, PPS, and PA66. In this case, the possibility that the positive electrode bus bar 4 and the negative electrode bus bar 5 are short-circuited can be reduced. The cover member 6 can be omitted.

  The configuration for realizing the position regulation of the positive current collector plate 15 and the negative current collector plate 16 in the width direction by the holding member 9 is not limited to the configuration of the above embodiment. For example, the end surface 15c may be in contact with the side surface 91a in the width direction, and the end surface 15d may be separated from the side surface 92a in the width direction. Even in this case, the relative position in the width direction of the positive electrode tab 15b with respect to the storage cell 7A can be defined by the protrusion 91A. Further, the end surface 15c may be separated from the side surface 91a in the width direction, and the end surface 15d may be in contact with the side surface 92a in the width direction. Even in this case, the relative position in the width direction of the positive electrode tab 15b with respect to the storage cell 7A can be defined by the protrusion 92A.

  Similarly, the end surface 16c may be in contact with the side surface 91b in the width direction, and the end surface 16d may be separated from the side surface 92b in the width direction. Even in this case, the relative position in the width direction of the negative electrode tab 16b with respect to the storage cell 7A can be defined by the protrusion 91B. Further, the end surface 16c may be separated from the side surface 91b in the width direction, and the end surface 16d may be in contact with the side surface 92b in the width direction. Even in this case, the relative position in the width direction of the negative electrode tab 16b with respect to the storage cell 7A can be defined by the protrusion 92B.

  Further, when the end surface 15c is in contact with the side surface 91a in the width direction, the side surface 91a and the end surface 4b may be in contact with each other in the width direction, and the side surface 92a and the end surface 4c are separated in the width direction. Also good. When the end surface 15d is in contact with the side surface 92a in the width direction, the side surface 92a and the end surface 4c may be in contact with each other in the width direction, and the side surface 91a and the end surface 4b may be separated in the width direction. . Similarly, when the end surface 16c is in contact with the side surface 91b in the width direction, the side surface 91b and the end surface 5b may be in contact with each other in the width direction, and the side surface 92b and the end surface 5c are separated in the width direction. May be. When the end surface 16d is in contact with the side surface 92b in the width direction, the side surface 92b and the end surface 5c may be in contact with each other in the width direction, and the side surface 91b and the end surface 5b may be separated in the width direction. .

  The height of the protrusions 91A and 92A may be lower than the thickness of the positive electrode tab 15b. The height of the protrusions 91B and 92B may be lower than the thickness of the negative electrode tab 16b. The holding member 9A only needs to include at least one of the protruding portions 91A, 91B, 92A, and 92B. Hereinafter, the first modification and the second modification will be described.

(First modification)
FIG. 9 is a cross-sectional view of the power storage device according to the first modification. The power storage device 1A shown in FIG. 9 is mainly different from the power storage device 1 in that recesses 93A and 93B are provided in the holding member 9A instead of the configuration in which the holding member 9A includes the protruding portions 91A, 91B, 92A, and 92B. Is different.

  The recess 93A is provided on the top surface 9a of the holding member 9A. The recess 93A is located under the positive electrode bus bar 4 and has a shape that fits with the positive electrode tab 15b of the positive electrode current collector plate 15 in the width direction. The recess 93A penetrates the holding member 9A in the stacking direction. The depth (length in the height direction) of the recess 93A is smaller than the thickness (length in the height direction) of the positive electrode tab 15b.

  The recess 93B is provided on the top surface 9a of the holding member 9A. The recess 93B is located under the negative electrode bus bar 5 and has a shape that fits with the negative electrode tab 16b of the negative electrode current collector plate 16 in the width direction. The recess 93B penetrates the holding member 9A in the stacking direction. The depth (length in the height direction) of the recess 93B is smaller than the thickness (length in the height direction) of the negative electrode tab 16b.

  In the power storage device 1A, since the positive electrode tab 15b fits into the recess 93A in the width direction, a relative position in the height direction and width direction of the positive electrode tab 15b with respect to the storage cell 7A is defined by the recess 93A. That is, the recessed portion 93A functions as a defining portion (first defining portion) that defines the position of the positive electrode tab 15b (positive electrode current collector plate 15) in the height direction and the width direction. Thereby, since the relative position in the height direction and the width direction of the positive electrode current collector plate 15 with respect to the power storage cell 7A is defined, the main body can be arranged with respect to the current collector 12 functioning as the positive electrode terminal of the power storage cell 7A. The position of the portion 15a is prevented from shifting.

  Similarly, in the power storage device 1A, since the negative electrode tab 16b fits into the recess 93B in the width direction, the relative position in the height direction and width direction of the negative electrode tab 16b with respect to the storage cell 7A is defined by the recess 93B. . That is, the concave portion 93B functions as a defining portion (second defining portion) that defines the position of the negative electrode tab 16b (negative electrode current collector plate 16) in the height direction and the width direction. Thereby, since the relative position in the height direction and the width direction of the negative electrode current collector plate 16 with respect to the power storage cell 7A is defined, the main body is opposed to the current collector 12 functioning as the negative electrode terminal of the power storage cell 7A. The position of the portion 16a is prevented from shifting.

  Therefore, the same effect as the power storage device 1 can be obtained in the power storage device 1A. Any one of the end faces 15c and 15d only needs to be in contact with the side surface of the recess 93A in the width direction. Even in this case, the relative position in the width direction of the positive electrode tab 15b with respect to the storage cell 7A can be defined by the recess 93A. Similarly, any one of the end surfaces 16c and 16d may be in contact with the side surface of the recess 93B in the width direction. Even in this case, the relative position in the width direction of the negative electrode tab 16b with respect to the storage cell 7A can be defined by the recess 93B.

  In power storage device 1A, since the depth of recess 93A is smaller than the thickness of positive electrode tab 15b, the position of positive electrode bus bar 4 in the width direction cannot be defined by recess 93A. However, by defining the position of the positive electrode current collector plate 15 in the width direction, the positive electrode current collector plate 15 (positive electrode tab 15b) and the storage cell 7A move together in the width direction. For this reason, even if force is applied to each power storage cell 7 along the width direction due to vibration, the power storage cell 7A and the positive electrode current collector plate 15 are integrated, so that it is difficult to move in the width direction. Thereby, the shearing stress applied along the width direction to the welded portion W1 between the positive electrode bus bar 4 and the positive electrode current collector plate 15 can be reduced. For the same reason, the shear stress applied along the width direction to the welded portion W2 between the negative electrode bus bar 5 and the negative electrode current collector plate 16 can be reduced. As a result, it is possible to improve the vibration resistance of the power storage device 1A. In the power storage device 1, the same effect can be obtained even when the height of the protrusions 91A and 92A is lower than the thickness of the positive electrode tab 15b and the height of the protrusions 91B and 92B is lower than the thickness of the negative electrode tab 16b. It is done.

(Second modification)
FIG. 10 is a plan view partially showing a power storage device according to a second modification. FIG. 11A and FIG. 11B are perspective views showing the electricity storage cell shown in FIG. 10 together with the positive electrode current collector plate and the negative electrode current collector plate. 10B is that the bending direction of the negative electrode tab 16b is the same as the bending direction of the positive electrode tab 15b, and that the holding member 9B includes protrusions 91B and 92B instead of the holding member 9A. This is mainly different from the power storage device 1.

  A positive electrode tab 15b is arranged on the holding member 9A (the top surface 9a of the holding member 9A). A negative electrode tab 16b is arranged on the holding member 9B (the top surface 9a of the holding member 9B). The holding member 9A regulates the displacement of the positive electrode current collector plate 15 in the height direction and the width direction. The holding member 9B regulates the displacement of the negative electrode current collector plate 16 in the height direction and the width direction.

  In the power storage device 1B, the positive electrode tab 15b is in contact with the top surface 9a of the holding member 9A in the height direction and is supported by the top surface 9a. Therefore, the relative position in the height direction of the positive electrode tab 15b with respect to the power storage cell 7A. Is defined. Further, since the end surface 15c of the positive electrode tab 15b is in contact with the protruding portion 91A and the end surface 15d of the positive electrode tab 15b is in contact with the protruding portion 92A, the relative position in the width direction of the positive electrode tab 15b with respect to the storage cell 7A protrudes. Part 91A, 92A. That is, the protruding portions 91A and 92A (side surfaces 91a and 92a) function as a defining portion (first defining portion) that defines the position of the positive electrode tab 15b (positive electrode current collector plate 15) in the width direction. Thereby, since the relative position in the height direction and the width direction of the positive electrode current collector plate 15 is defined with respect to the storage cell 7A, the position of the main body portion 15a is shifted with respect to the outer surface 12a of the storage cell 7A. It is suppressed. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cell 7A and the positive electrode current collector plate 15.

  Similarly, in the power storage device 1B, the negative electrode tab 16b abuts on the top surface 9a of the holding member 9B in the height direction and is supported by the top surface 9a. Specific position is defined. Further, since the end surface 16c of the negative electrode tab 16b is in contact with the protruding portion 91B and the end surface 16d of the negative electrode tab 16b is in contact with the protruding portion 92B, the relative position in the width direction of the negative electrode tab 16b with respect to the storage cell 7B protrudes. Defined by the portions 91B and 92B. That is, the protruding portions 91B and 92B (side surfaces 91b and 92b) function as a defining portion (second defining portion) that defines the position of the negative electrode tab 16b (negative electrode current collector plate 16) in the width direction. Thereby, since the relative position in the height direction and the width direction of the negative electrode current collector plate 16 with respect to the storage cell 7B is defined, the position of the main body portion 16a is shifted with respect to the outer side surface 12b of the storage cell 7B. It is suppressed. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cell 7B and the negative electrode current collector plate 16.

  Further, in the power storage device 1B, since the height direction and the width direction of each holding member 9 are aligned, the main body portion 15a with respect to the outer surface 12a of the power storage cells 7A and 7B adjacent to each other with the main body portion 15a interposed therebetween. Is prevented from shifting. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cells 7A and 7B and the positive electrode current collector plate 15. Similarly, the position of the main body portion 16a is suppressed from the outer surface 12b of the storage cells 7A and 7B adjacent to each other with the main body portion 16a interposed therebetween. Therefore, an increase in resistance component is suppressed in the conductive path between the storage cells 7A and 7B and the negative electrode current collector plate 16.

  Therefore, the same effect as that of the power storage device 1 can be obtained in the power storage device 1B.

  DESCRIPTION OF SYMBOLS 1,1A, 1B ... Power storage device, 2 ... Cell stack, 4 ... Positive electrode bus bar (first bus bar), 5 ... Negative electrode bus bar (second bus bar), 7 ... Power storage cell, 7A ... Power storage cell (first power storage cell), 7B: Storage cell (second storage cell), 9: Holding member, 9A: Holding member (first holding member), 9B: Holding member (second holding member), 10: Bipolar electrode (electrode), 12a ... Outer surface (First surface), 12b ... outer side surface (second surface), 15 ... positive electrode current collector plate (first current collector plate), 15a ... main body portion (first main body portion), 15b ... positive electrode tab (first tab) 15c, 15d ... end face, 16 ... negative electrode current collector plate (second current collector plate), 16a ... main body part (second main body part), 16b ... negative electrode tab (second tab), 16c, 16d ... end face, 91A, 92A ... Projection (first defining part), 91B, 92B ... Projection (second defining part), 93A ... Concave First specified portion), 93B ... recess (second specified portion).

Claims (8)

A cell stack including a plurality of power storage cells stacked along a first direction via a current collector plate;
Each of the plurality of power storage cells includes a plurality of electrodes stacked along the first direction, and a holding member that holds the plurality of electrodes.
A first power storage cell of the plurality of power storage cells is disposed between the first current collector plate and the second current collector plate in the first direction,
The first current collecting plate is in contact with a first body portion that is in contact with a first surface of the first storage cell in the first direction, and along a second direction that intersects the first direction from the first body portion. A first tab that protrudes and extends along the first direction;
The first tab is disposed on a first holding member of the first storage cell,
The power storage device, wherein the first holding member includes a first defining portion that defines a position of the first tab in a third direction intersecting the first direction and the second direction. The first tab has an end surface in the third direction;
The first holding member protrudes along the second direction and has a protruding portion facing the end surface in the third direction,
The power storage device according to claim 1, wherein the first defining portion is the protruding portion. The first holding member is provided with a recess that fits with the first tab,
The power storage device according to claim 1, wherein the first defining portion is the recess. The second current collector plate is in contact with a second surface opposite to the first surface in the first direction of the first power storage cell, and from the second body portion to the second direction. A second tab protruding along the first direction and extending in the first direction,
The second tab is disposed on the first holding member;
4. The power storage device according to claim 1, wherein the first holding member includes a second defining portion that defines a position of the second tab in the third direction. 5. A second power storage cell of the plurality of power storage cells is adjacent to the first power storage cell via the second current collector plate in the first direction,
The second current collector plate is in contact with a second surface opposite to the first surface in the first direction of the first power storage cell, and from the second body portion to the second direction. A second tab protruding along the first direction and extending in the first direction,
The second tab is disposed on a second holding member of the second storage cell,
4. The power storage device according to claim 1, wherein the second holding member includes a second defining portion that defines a position of the second tab in the third direction. 5. A first bus bar extending along the first direction and joined to the first tab in the second direction;
A second bus bar extending along the first direction and joined to the second tab in the second direction;
The power storage device according to claim 4 or 5, further comprising:   The power storage device according to any one of claims 1 to 6, wherein a length of the first main body portion in the third direction is smaller than a length of the first holding member in the third direction.   The power storage device according to claim 7, wherein the length of the first main body portion in the third direction is equal to a length of the plurality of electrodes in the third direction.

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